The present invention relates generally to a heating type hair waving appliance.
A conventional way to confer a durable hair wave is to allow a waving agent to react on hair at room temperature. This is called "cold waving." However, in this instance the waving agent, for example, thioglycolate, should be strong because it reacts on hair at room temperature. There is a great risk that the waving agent will damage the skin of a beautician and the hair of a patron. In addition, since the period where the waving agent reacts on the hair is determined primarily by the judgement and experience of a beautician, the degree of hair waving is occasionally too much or too little. Lately, some approaches to overcome the defects noted above have been suggested, that is, the use of heating types of hair waving appliances wherein hair is heated before the reaction of a waving agent. One method of waving hair involves curling the hair about heated curler rods to heat the hair and allow a waving agent to react on the hair. An alternative method of waving hair involves supplying hot air to hair containing a waving agent to heat the hair during the reaction of the waving agent. See, for example, German Pat. No. 1059160 issued on Apr. 26, 1962 and No. 1079801 issued on Sept. 13, 1962.
While these prior art appliances were provided with temperature sensors for providing a control for temperatures of the heater elements contained therein, the temperature sensors were adapted to sense the temperature of the atmosphere within a head supporting assembly. Therefore, the prior art sensors could not provide accurate detection of the hair itself.